I was sent the following board and South asked for help. They let the opponents play 3 Spades and scored poorly.
North East South West
♠️ 8 AQJ9 54 KT7632
♥️ AKQT842 3 J6 975
♦️ 752 KT98 A643 QJ
§ K5 Q843 AJT96 72
East opens 1 Club (a Diamond is better) and South passes. West responds 1 Spade and North must stop to think. He is way too strong for 2 or 3 Hearts. He decides his Hearts are self-supporting and counts 20 points. He sees two options.
If North wants to try to shut out the opponents, he can jump to 4 Hearts with his favorable vulnerability. Partner would know that he has 7 sure tricks if they play Rule of 2 or 3, but would have no idea if they disdain that for "Modern Preempts". If the opponents were to compete to 4 Spades, he couldn't bid again and partner might not see 11 tricks.
North instead decides to double (Big) to try to get information from partner in case the opponents compete or there's a chance for slam. East raises to 2 Spades and South jumps to 4 Diamonds to show his best unbid suit and 9-12 points.
Now North can rebid 4 Hearts and if the opponents compete to 4 Spades, he can compete to 5 Hearts and make it easily.
Good luck to you all and stay well. Dave